Most utilities, such as those that provide electric, water, gas and telephone service, bury their conveyances (i.e., pipes and cables) underground both for reasons of safety and esthetics. Underground burial also protects such conveyances from direct exposure to the elements. Once a utility buries a conveyance, the utility marks the location on a map relative to an existing physical landmark, such as a building, road, or bridge, to facilitate location of the conveyance in the event of a repair. Using a physical landmark as a point of reference incurs the disadvantage that such landmarks can and do undergo change. For example, a building may undergo renovation or even demolition whereas a road may under widening, thus altering the previously existing physical relationship between the landmark and the buried conveyance. Consequently, relying on the physical relationship between a landmark and the conveyance may not always yield an accurate indication of the location of the conveyance.
To facilitate greater precision in the location of their conveyances, utilities often use electromagnetic detection techniques. One such locating technique is disclosed in U.S. Pat. No. 5,644,237, issued in the names of Hossein Eslambolchi and John Huffinan on Jul. 1, 1997 and assigned to the assignee of the present invention. The Eslambolchi et al. '237 patent (hereinafter incorporated by reference) describes and claims a locating technique, whereby a first transmitter impresses a first locating tone on a conveyance to allow a technician to generally locate the conveyance using a signal-locating receiver. Additionally, a second transmitter provides a coded, near DC signal on the conveyance to allow the technician, using a second receiver, to precisely locate the conveyance of interest.
Service providers, such as AT&T, often utilize a large number of transmitters for providing cable-locating tones on their buried conveyances. Often the transmitters are located at remote unmanned facilities, requiring that a technician travel to such a facility to undertake an upgrade of the operating software of the cable-locating transmitter. Thus, to undertake an expeditious software upgrade of all of the cable-locating transmitters associated with a large network of underground conveyances will require a large commitment of personnel so that each transmitter can receive the new operating software typically via an EPROM replacement at within the same time interval. Without committing a large number of personnel, software upgrades will not occur within the same time frame, creating a mix of cable-locating transmitters with different operating software, which is undesirable from a standpoint of network administration.
Thus, there is a need for a technique for controlling the upgrading the operating software each of a plurality of remote cable-locating transmitters.